Detuning and AM Protection

The FCC mandates protection of AM stations!

Constructing a communications tower without proper protection of nearby AM broadcast stations can trigger construction delays, FCC violations, and costly penalties.

LBA’s proven engineering approach, unsurpassed hardware, and on-cost/on-time turnkey performance has made it the leader in AM protection services, nationwide. LBA has over 40 years of AM experience, including some of the most complex detuning projects ever!
 

What AM protection is FCC mandated?
Present FCC regulations require AM protection when construction or modification of towers or other structures that might distort the AM station’s pattern is proposed within 1.0 kilometers of a non-directional (single tower) broadcast transmitter site and 3.0 kilometers of a directional (multi-tower) site.

In such cases, each affected AM station must be notified. The proponent of the construction must make this notification and take appropriate steps to protect the AM station antenna pattern. LBA uses a proprietary algorithm based upon measurements of hundreds of similar towers to predict what actions, if any, must be undertaken. This ensures the most economical resolution of AM detuning issues.

In the most severe cases, the installation and adjustment of detuning equipment may be required to nullify the effect of the new structure. LBA has over 40 years experience in the design and manufacture of AM detuning equipment, as well as its field adjustment.

Why does the FCC require this screening?
Interaction between AM antenna systems and cellular and other wireless towers is becoming more common as the density of cell sites increases. This interaction is generally independent of the frequencies in use on the wireless tower, and relates solely to the proposed tower characteristic at AM frequencies (540 – 1710 kHz).

When the cell tower is a significant portion of a wavelength in the AM broadcast band, mutual coupling occurs between a new tower and the AM tower. This mutual coupling induces AM RF power in the cellular tower which then will reradiate a portion of this AM power. Thus, the wireless tower effectively becomes another tower in the AM station’s system, changing its FCC licensed radiation pattern.

Whether you are building a tower within 2 miles of an AM station, or need pre-build analysis of a complex network of sites, LBA is ready to be your partner with full AM protection support services. Click to the right for do it yourself screenings or contact LBA directly for hassle-free comprehensive bulk site screenings!  Let's talk!

For a quotation or technical assistance, use the

or contact Cathy Scott via email or call  800-522-4464